BackgroundThe aim of this systematic review and meta-analysis was to determine the performance of magnetic resonance imaging (MRI) in the diagnosis of bowel inflammation and disease activity in Crohn's disease (CD). MethodsMEDLINE, Embase and Web of Science databases of biomedical literature were systematically searched to identify studies that investigated the diagnostic accuracy of MRI in diagnosing bowel inflammation and disease activity in CD by comparing it with reference standards. Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess study quality. The summary sensitivity and specificity were estimated using the bivariate model, and hierarchical summary receiver operating characteristic (HSROC) parameters were calculated and plotted. ResultsOf 5492 citations of interest, 34 articles contained the diagnostic accuracy data. Of these, results for the small bowel and the colorectum were reported separately in 19 studies and jointly by 21 studies. The meta-analytic summary sensitivity and specificity under the bivariate model were 90.9% (95% CI, 85.8%–94.2%) and 90.2% (95% CI, 81.9%–95.0%), respectively. The sensitivities and specificities of individual studies ranged from 55% to 100% and 51% to 100%, respectively. Substantial heterogeneity was observed in both sensitivity (I2=84.9%) and specificity (I2=78.8%). The HSROC curve also showed considerable heterogeneity between studies. ConclusionAlthough the meta-analytic summary accuracy of MRI was high for the diagnosis of bowel inflammation in CD, the summary estimates might be unreliable due to the presence of high heterogeneity.